Glass container with roll-on closure

ABSTRACT

A glass container in the form of a growler is provided with a re-sealable roll-on closure. An improved construction is provided for the container enabling it to handle higher pressures in which minimum glass wall thicknesses are optimized to provide necessary strength for the container, yet the construction conserves amounts of glass used. In a preferred embodiment, the container is capable of holding a 64 oz beverage, and the container includes a re-sealable roll-on 38 mm closure with a capacity to hold up to 3.00 v/v CO 2  pressure at 145° F. A minimum glass wall thickness along a sidewall of the container starting from a mid-neck down to a heel portion of the container is 2.5 mm. An integral glass handle is provided with a minimum break strength of 170 pounds. In a preferred embodiment, the container has a maximum to minimum sidewall thickness ratio of approximately 2:1 and a base thickness ratio of approximately 1.5:1.

FIELD OF THE INVENTION

The invention relates to glass containers, and more particularly, toglass containers designed to hold carbonated beverages at relativelyhigh pressures, including a roll-on cap or crown used to effectivelyseal the container to prevent leakage after opening.

BACKGROUND OF THE INVENTION

Glass or ceramic jugs, often referred to as “growlers”, havetraditionally been used to hold malt beverages such as beer that hasbeen brewed in small craft breweries. Prior to the advent of largecommercial breweries, most malt beverages were sold by small localbreweries that had little or no bottling capabilities. The growlers wereused to allow customers to purchase beverages from the brewery and takehome the beverages in relatively large containers that could then bepoured later into individual glasses for consumption. The most popularsize for growlers is the ½ US gallon (1,900 ml); however there are othergrowler sizes that are well-known to include 1 gallon sizes and ¼ gallonsizes. The most common type of handle for growlers is an integral glasshandle; however, metal handles have also been used in more ornategrowler designs.

Recently, there has been a resurgence in craft breweries. While bottlingcapabilities may now be more available to smaller craft breweries, manyof these breweries have opted for continued use of the growler typecontainer for historical and marketing purposes. Additionally, manylarger breweries have entered into the craft brewery market, and havealso chosen in some circumstances to use the growler container formarketing purposes. Regardless of the specific reason for current use ofgrowlers, there continues to be certain advantages and disadvantagesassociated with the use of these types of containers.

One of the advantages of the growler is that it has a storage capacityfor holding a quantity of a beverage that is likely to be consumed bythe consumer within a relatively short period of time, thereby enablingthe consumer to purchase a convenient bulk sized quantity without havingto purchase a much larger keg sized quantity that likely would not beconsumed by the consumer without significant waste. Another advantage isthat the growler provides an economical solution for storage anddistribution of the beverage, and can be more cost effective than use ofmultiple containers, such as 12 ounce glass containers.

There are a number of disadvantages associated with growlers. One cleardisadvantage is that unless the beverage is consumed within a shortperiod of time, the growler is incapable of maintaining adequatepressure within the container to keep the beverage adequatelycarbonated. Accordingly, the beverage soon loses carbonation and goes“flat”, which is a condition which most beer consumers agree isinadequate for consumption of the product. Another disadvantage is that,although many growlers are intended to be reused, they are difficult toadequately clean and sterilize because of the relatively small size ofthe container mouth. The small size of the opening makes accessing therelatively large interior volume for cleaning and sterilizationdifficult. The small size of the opening can also cause a vacuum or“glugging” when the beverage is being poured from the growler, resultingin an inadequate pour.

Yet another clear disadvantage of traditional growlers is that the glassmaterial is fragile as compared to metal containers, and therefore thegrowlers with their relatively large size are particularly prone tobreakage. Glass continues to be a preferred type of container materialfor consumers as compared to metal containers; many consumer tests showthat a significant number of consumers believe the taste of a beverageis compromised if stored and dispensed from a metallic container.Further, sunlight can easily damage a stored beverage, and growlersexposed to sunlight increase the chance that the beverage will beconsumed in a flavor degraded state. Some malt beverages areparticularly sensitive to sunlight and can quickly degrade after evenrelatively short periods of sunlight exposure.

Therefore, there is a need to provide a relatively large sized glasscontainer that can hold a carbonated beverage such as beer at adequatecarbonation levels in which the container has the ability to withstandgreater internal pressures and hold those pressures for an extendedperiod of time to prevent the beer from going flat. Further, there is aneed to provide such bulk sized glass containers that may be more easilycleaned. Further, there is a need to provide such bulk sized glasscontainers that allow the beverage to be more easily poured to createthe characteristic “head” when the beverage is poured.

SUMMARY OF THE INVENTION

In accordance with the present invention, a glass container with are-sealable roll-on cap is provided. The container also provides adesign in which the container is capable of withstanding relatively highpressures to maintain a carbonated beverage stored within the containerat desired carbonation levels thereby maximizing beverage consumptioncharacteristics.

According to a preferred embodiment, the container includes are-sealable roll-on 38 mm closure that achieves two distinct benefits.First, the 38 mm closure is considered sized for a “wide-mouth” opening,and is therefore larger than traditional closure sizes. The larger sizedopening for the glass container allows for easier access to the interiorspace of the container for cleaning and sterilization purposes. Second,the 38 mm sized opening allows for better pourability of the beverage toavoid the vacuum or “glug” associated with smaller sized openings. Thisvacuum or “glug” inhibits a smooth pouring action, and can prevent theconsumer from pouring a desired sized head of the malt beverage. It iswell known that for malt beverages, some amount of head is desirable forboth taste and product presentation purposes.

Also according to a preferred embodiment, an improved construction isprovided enabling the container to handle higher pressures in which theminimum glass wall thicknesses are optimized to provide the necessarystrength for the container, yet conserve the amount of glass used. Theminimum glass wall thickness along a portion of the container startingfrom the mid-neck down to a heel portion of the container is 2.5 mm.However, the average preferred thickness may vary as described below inthe detailed description, which also provides additional benefits withrespect to various loading conditions and manufacturability.

Further in accordance with a preferred embodiment, an integrated glasshandle is provided with a minimum break strength that exceeds normalbreak strength requirements for similar glass containers.

With respect to pressure requirements, the preferred embodiment providesfor a container to hold 64 fluid ounces (or ½ gallon) of beverage inwhich the container is able to withstand at least 3.0 volumes of CO₂ pervolume of beer and internal beer temperatures up to 145° F. forpasteurization. At the container manufacturing location, a theoreticalpressure strength of the containers is set for approximately 225 psiinterior pressure taking into account a factor of safety for loss incontainer strength. More specifically, during handling of containers atthe manufacturing location, the containers inherently lose strengththrough contact or “bruising”, and therefore testing is conducted toconfirm pressure strength when the containers are ready for shipment.The containers at this stage preferably must pass a pressure test forpressures greater than 150 psi over a one minute testing period. As thecontainers are further handled during shipment, there can be additionalloss in strength and therefore, the containers undergo a furtherstrength test at the filling location, such as a brewery, in which aminimum strength of greater than 100 psi must be achieved. A failure atthis stage typically results in rejection of the lot or group ofcontainers corresponding to the failed test sample container(s).

With respect to the roll-on 38 mm closure, the closure is designed tohold up to 3.00 v/v CO₂ pressure at 145° F. With respect to the breakstrength for the glass handle, the design of the present inventionprovides for a minimum break strength of 170 pounds. General dimensionsfor the container are such that container is capable of being handled bymany standard bottle filling production lines. In a preferredembodiment, the height of the container is a minimum of 11.00 inches,the maximum diameter is less than or equal to 5.20 inches, and thebearing surface is approximately 4.0 inches in diameter.

Considering the above features of the invention, in one aspect theinvention can be considered a glass container comprising: (i) a topportion including an opening; (ii) a base; (iii) a sidewallinterconnecting the top portion and base; (iv) a 38 mm roll-on closurecovering said opening; (v) a handle mounted to said container, whereinthe sidewall has a minimum thickness of 2.5 mm and an average thicknessof 4.5 mm to 5.5 mm, and wherein said container is sealed to hold up to3.0 v/v CO₂ pressure at 145° F.

In another aspect of the invention, it can also be considered a glasscontainer comprising: (i) a top portion including an opening; (ii) abase; (iii) a sidewall interconnecting the top portion and base; (iv) a38 mm roll-on closure covering said opening; (v) a handle mounted tosaid container; wherein said container is sealed to hold up to 3.0 v/vCO₂ pressure at 145° F., and wherein said sidewall of said container hasa preferred maximum to minimum thickness ratio of approximately 2:1.

In yet another aspect of the invention, it can also be considered aglass container comprising: (i) a top portion including an opening; (ii)a base; (iii) a sidewall interconnecting the top portion and base; (iv)a 38 mm roll-on closure covering said opening; (v) a handle mounted tosaid container; and wherein said container has a glass thicknessdistribution including: (a) a minimum thickness of 2.5 mm; (b) anaverage thickness of said sidewall of 4.5 mm to 5.5 mm; (c) saidcontainer has a heel located between the sidewall and base, said heelhaving an average thickness of 4.0 to 5.0 mm; and (d) said base includesa bearing surface formed along a peripheral portion of the base, saidbearing surface having an average thickness of 6.5 to 7.5 mm.

Other features and advantages of the invention will become apparent froma review of the following detailed description, taken in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating the glass container of thepresent invention;

FIG. 2 is a side elevation view of the glass container of FIG. 1;

FIG. 3 is a vertical section taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary perspective view of the upper portionof the container and a blank disposed above the upper end or finish ofthe container, the blank representing a closure or cap prior to beformed around the threads of the finish;

FIG. 5 is another enlarged fragmentary perspective view of the upperportion of the container showing the closure placed over the threads ofthe upper end of the container; and

FIG. 6 is a table providing information regarding a preferred thicknessdistribution for the container according to a preferred embodiment.

DETAILED DESCRIPTION

Referring to FIGS. 1-3, a container 10 of the present invention shown.The container 10 can be referred to as a growler, a container sized forholding a bulk volume of a beverage, and especially adapted for holdingcarbonated beverages such as beer. The container has a sidewall 12, ashoulder 14 disposed above an upper portion 16 of the sidewall, aconverging portion 18, and a neck 20 disposed above the convergingportion 18. The upper end of the container, also referred to as thefinish 22, has threads 24 formed thereon. An integral handle 26 isprovided, the handle 26 having an upper end 28 that attaches to the neck20 at a base 31, and a lower end 30 that attaches to the convergingportion 18 at base 31. The bases 31 of the upper and lower ends 28, 30of the handle 26 are enlarged as shown which contributes to theincreased break strength, as discussed below. The loop 27 of the handleis adequately sized for carrying, and the loop 27 creates an arcuateshaped opening 29 for use as a carrying handle.

The sidewall 12 may be further described as including the upper portion16, a mid portion 32, and a lower portion 34. The sidewall 12 forms acylindrical shape. Below the sidewall 12 is a converging heel 36 thatterminates at a bearing surface 38. The bearing surface 38 is theexposed lower surface of the container that makes contact with theobject on which the container is placed. The lower end of the containerhas a concave shape, and a center bottom portion 40 of the lower endcorresponds to a small circular area centered on the lower end having adiameter of approximately 1 inch. Surrounding the center bottom portion40 is the mid-bottom portion 42, defined by the area between the bearingsurface 38 and the small circular area defining the center bottom 40.

In the preferred embodiment, the diameter of the container as measuredfrom the diameter of the sidewall is less than or equal to 5.20 inches.The bearing surface defines a smaller diameter area of less than orequal to 4.00 inches. The overall height of the container in thepreferred embodiment is a minimum of 11 inches.

Referring to FIG. 4, the container 10 is shown along with a blank orunthreaded shell 50 that is formed into a cap or closure in a subsequentcapping process. More specifically, a roll-on type closure is initiallyprovided as the blank 50, and when the container passes a cappingstation during a filling process, the blank 50 is compressed to conformto the finished shape of the upper end of the container. The blank 50 ismade from a compressible metal, such as aluminum. The interior upperplanar surface of the blank 50 has a compressible seal or liner (notshown) attached thereto. A capping machine (not shown) exerts a downwardpressure that creates a positive seal on the liner of the blank 50 asthe liner is pressed against the upper surface of the finish 22. Next,rollers on a capping head of the capping machine shape the malleableblank 50 to conform to the exact contour of the threads 24 on thecontainer.

As shown in FIG. 5, the blank 50 has been compressed to form the cap orclosure 52 with threads that match the threads 24 of the finish 22.According to the preferred embodiment, the container includes are-sealable roll-on 38 mm closure that achieves two distinct benefits:the 38 mm closure is larger than traditional sizes of closures used ongrowlers and therefore allows for easier access to the interior of thecontainer for cleaning and sterilization purposes, and second, the 38 mmsized opening allows for better pourability of a beverage from thecontainer. Particularly for malt beverages, the larger size mouth of thecontainer provides a better opportunity for air to enter the containeras the beverage is poured from the container, therefore avoiding avacuum or “glug” as the beverage is poured. The container in other wordscan be held at a larger range of angles when pouring to avoid the vacuumeffect.

An improved construction is provided for the container enabling it tohandle higher pressures in which the minimum glass wall thicknesses areoptimized to provide the necessary strength for the container, yetconserve the amount of glass used. Through extensive testing, glassthickness distribution was modified in the present invention in order toprovide a container that could handle increased pressure requirements,yet still resulted in an economic container that did not require excessamounts of glass material. Through this testing, it was determined thata ratio could be developed with regard to preferred minimum and maximumglass thickness distributions that met minimum strength requirements,but also met bottling and material requirements that limit the thicknessof the container. For example, a container having an excessively thicksidewall may not meet required container dimension specifications, ormay not meet required volume specifications, such as overflow capacity,in which case the thickened sidewall results in an incrementally smallerinterior volume. For the sidewall area of the container, it wasdetermined that a ratio of 2.0 to 1.0 (2:1) was preferable with respectto glass thickness in which the minimum allowable thickness was 2.5 mm.For the base area of the container, it was determined that a ratio of1.5 to 1.0 (1.5:1) was preferable with respect to glass thickness inwhich the minimum allowable thickness was 5.1 mm. This base area of thecontainer includes the center bottom 40, mid-bottom 42, and bearingsurface 38 areas. As mentioned, one distinct disadvantage associatedwith growlers is that the containers do not have the capability to holdpressure with a re-sealable roll-on closure to facilitate acceptablecarbonation levels for a stored beverage. Prior art growlers may includethreaded closures, but not roll-on type closures with liners thatprovide a pressurized sealing capability. The preferred embodiment ofthe present invention provides for a glass container to accommodate a 64ounce or ½ gallon beverage in which the container is able to withstandat least a 225 psi interior pressure.

As is well known with malt beverages, adequate levels of carbonation arecritical for achieving the body or “fullness” of the beverage.Carbonation also provides the foaming capability and contributes as animportant flavor component. Carbonization of a malt beverage is achievedin part through the brewing process. Carbonation levels are typicallyraised for the malt beverage prior to bottling in a forced carbonationstep, providing necessary carbonation levels for sale of the beverage.One industry standard measure of carbonation is a measure of volumes ofcarbon dioxide per volume of beer, expressed as a ratio “v/v”. Forbottled and canned beverages (12 or 16 oz sizes), the carbonation levelsmay typically be between 2.2 and 2.8 v/v. However, for growlers, maximumcarbonation levels are typically about 2.0 v/v. This level ofcarbonation is clearly inadequate for any long term storage of abeverage. Further as mentioned, prior art growlers are not pressuresealed to the same capability as smaller 12 oz. containers, andtherefore, optimum carbonation is lost prior to opening of the growlerin many instances. Once a prior art growler is opened, carbonationlevels quickly drop and unless the beverage is entirely consumed, theremaining beverage goes flat within a short period of time.

Due to the specific design of the glass wall thicknesses along with useof the re-sealable 38 mm closure, the container of the present inventionis capable of holding and maintaining carbonation levels up to 3.00 v/vCO₂ at 145° F. At this level of carbonation, the beverage stands a muchbetter chance of maintaining an optimum level of carbonation even afterthe container is opened. Since the container is re-sealable, the rate atwhich carbonation is lost is greatly slowed as compared to the prior artgrowlers. Therefore, the container of the present invention provides asolution for maintaining optimum levels of beverage carbonation, as wellas to extend the shelf life of the beverage with the increased level ofcarbonation maintained.

The minimum glass wall thickness along the portion of the containerdefined from the neck 20 down to the heel 36 is 2.5 mm. However, theaverage preferred thickness varies as set forth in the table of FIG. 6.Referring to this table, ranges for average preferred thicknesses forthe discrete portions or sections of the container are listed, alongwith minimum required thicknesses for most of the listed portions.Accordingly, in another aspect of the invention, an average thickness isalso contemplated as a measured parameter with respect to thicknesses ofthe container 10. These average thicknesses are achieved through acontainer forming process in which the average thicknesses comply withthe required minimum thicknesses, yet still enable the container to bemanufactured in standard glass manufacturing processes having inherentlimitations regarding how thin glass can be distributed withoutunacceptable numbers of manufacturing defects. For example, while theminimum required thickness for the container may be 2.5 mm for thesidewall 12, actually consistently achieving this minimum thickness instandard glass manufacturing processes is difficult; therefore, a factorof safety is added in the manufacturing process which inherently resultsin average thicknesses being greater than minimum required thicknesses.Again through testing, it was found that having the listed averagethicknesses according to the table of FIG. 6 results in overallmanufacturing benefits in which required glass distribution can beachieved through standard glass manufacturing processes, and thereforestill results in significant savings of glass.

Further in accordance with the preferred embodiment, the integratedglass handle 26 is provided with a minimum break strength that exceedsnormal break strength requirements for similar glass containers. Oneacceptable dimensioning of the loop 27 of the handle 26 includes a loopdiameter of 11-13 mm. With respect to the break strength for the glasshandle 26, the design of the present invention provides a minimum breakstrength of 170 pounds. The dimensioning of the handle, including theminimum base 31 thickness of between 5.5 and 6.5 mm, achieves thisstrength capability. The handle is therefore not oversized, is stilleasily grasped with one or more fingers of a consumer, and does notcreate such a large handle profile that otherwise would detract fromsome of the aesthetic and historical dimensions associated withgrowlers.

There are a number of advantages to the glass container of the presentinvention. A growler type container incorporates a larger, wide-mouthopening in combination with a re-sealable roll-on closure. The widemouth opening accommodates cleaning and disinfection of the container,and enhances pourability of malt type beverages. The re-sealable closureenables longer term storage of carbonated beverages at optimalcarbonation levels to enhance flavor characteristics and shelf life. Theintegral handle is capable withstanding forces in excess of standardbreak strength requirements.

What is claimed is:
 1. A glass container comprising: a top portionincluding an opening; a base; a sidewall interconnecting the top portionand base; a 38 mm roll-on closure covering said opening; a handlemounted to said container; wherein the sidewall has a minimum thicknessof 2.5 mm and an average thickness of 4.5 mm to 5.5 mm; and wherein saidcontainer is sealed to hold up to 3.0 v/v CO₂ pressure at 145° F.
 2. Theglass container, as claimed in claim 1, wherein: said container has aheel located between the sidewall and base, said heel having an averagethickness of 4.0 to 5.0 mm.
 3. The glass container, as claimed in claim1, wherein: said base includes a bearing surface formed along aperipheral portion of the base, said bearing surface having an averagethickness of 6.5 to 7.5 mm.
 4. The glass container, as claimed in claim1, wherein: said base includes a center bottom portion having an averagethickness of 9.0 to 10.0 mm.
 5. The glass container, as claimed in claim1, wherein: said base includes a mid bottom portion having an averagethickness of 8.0 to 9.0 mm.
 6. The glass container, as claimed in claim1, wherein: said container includes a shoulder disposed above an upperportion of the sidewall, said shoulder having an average thickness of4.7 to 5.7 mm.
 7. The glass container, as claimed in claim 1, wherein:said container includes a neck disposed between a shoulder and a finishof said container, said neck having an average thickness of 5.5 to 6.5mm.
 8. The glass container, as claimed in claim 1, wherein: saidcontainer includes a finish portion of said top portion, said finishportion having an average thickness of 3.5 to 4.5 mm.
 9. The glasscontainer, as claimed in claim 1, wherein: said sidewall of saidcontainer has a preferred maximum to minimum glass wall thickness ratioof approximately 2:1.
 10. The glass container, as claimed in claim 1,wherein: a volume of said container is adequate to hold a 64 oz amountof a beverage.
 11. The glass container, as claimed in claim 1, wherein:a diameter of said container is up to 5.20 inches.
 12. The glasscontainer, as claimed in claim 1, wherein: a contact diameter of saidcontainer along a bearing surface of said container is up to 4.0 inches.13. The glass container, as claimed in claim 1, wherein: said containerhas a minimum height of 11.0 inches.
 14. The glass container, as claimedin claim 1, wherein: said handle of said container has a minimum breakstrength of 170 lbs.
 15. The glass container, as claimed in claim 1,wherein: said container has a preferred maximum to minimum basethickness ratio of approximately 1.5:1.
 16. A glass containercomprising: a top portion including an opening; a base; a sidewallinterconnecting the top portion and base; a 38 mm roll-on closurecovering said opening; a handle mounted to said container; wherein saidcontainer is sealed to hold up to 3.0 v/v CO₂ pressure at 145° F.; andwherein said sidewall of said container has a preferred maximum tominimum thickness ratio of approximately 2:1.
 17. The glass container,as claimed in claim 16, wherein the sidewall has a minimum thickness of2.5 mm and an average thickness of 4.5 mm to 5.5 mm.
 18. The glasscontainer, as claimed in claim 16, wherein: said container has a heellocated between the sidewall and base, said heel having an averagethickness of 4.0 to 5.0 mm.
 19. The glass container, as claimed in claim16, wherein: said base includes a bearing surface formed along aperipheral portion of the base, said bearing surface having an averagethickness of 6.5 to 7.5 mm.
 20. The glass container, as claimed in claim16, wherein: said base includes a center bottom portion having anaverage thickness of 9.0 to 10.0 mm.
 21. The glass container, as claimedin claim 16, wherein: said base includes a mid bottom portion having anaverage thickness of 8.0 to 9.0 mm.
 22. The glass container, as claimedin claim 16, wherein: said container includes a shoulder disposed abovean upper portion of the sidewall, said shoulder having an averagethickness of 4.7 to 5.7 mm.
 23. The glass container, as claimed in claim16, wherein: said container includes a neck disposed between a shoulderand a finish of said container, said neck having an average thickness of5.5 to 6.5 mm.
 24. The glass container, as claimed in claim 16, wherein:said container includes a finish portion of said top portion, saidfinish portion having an average thickness of 3.5 to 4.5 mm.
 25. Theglass container, as claimed in claim 16, wherein: said container has apreferred maximum to minimum base thickness ratio of approximately1.5:1.
 26. The glass container, as claimed in claim 16, wherein: avolume of said container is adequate to hold a 64 oz amount of abeverage.
 27. The glass container, as claimed in claim 16, wherein: adiameter of said container is up to 5.20 inches.
 28. The glasscontainer, as claimed in claim 16, wherein: a contact diameter of saidcontainer along a bearing surface of said container is up to 4.0 inches29. The glass container, as claimed in claim 16, wherein: said containerhas a minimum height of 11.0 inches.
 30. The glass container, as claimedin claim 16, wherein: said handle of said container has a minimum breakstrength of 170 lbs.
 31. A glass container comprising: a top portionincluding an opening; a base; a sidewall interconnecting the top portionand base; a 38 mm roll-on closure covering said opening; a handlemounted to said container; and wherein said container has a glassthickness distribution including: (i) a minimum thickness of 2.5 mm;(ii) an average thickness of said sidewall of 4.5 mm to 5.5 mm; (iii)said container has a heel located between the sidewall and base, saidheel having an average thickness of 4.0 to 5.0 mm; (iv) said baseincludes a bearing surface formed along a peripheral portion of thebase, said bearing surface having an average thickness of 6.5 to 7.5 mm.32. The glass container, as claimed in claim 31, wherein: said baseincludes a center bottom portion having an average thickness of 9.0 to10.0 mm.
 33. The glass container, as claimed in claim 31, wherein: saidbase includes a mid bottom portion having an average thickness of 8.0 to9.0 mm.
 34. The glass container, as claimed in claim 31, wherein: saidcontainer includes a shoulder disposed above an upper portion of thesidewall, said shoulder having an average thickness of 4.7 to 5.7 mm.35. The glass container, as claimed in claim 31, wherein: said containerincludes a neck disposed between a shoulder and a finish of saidcontainer, said neck having an average thickness of 5.5 to 6.5 mm. 36.The glass container, as claimed in claim 31, wherein: said containerincludes a finish portion of said top portion, said finish portionhaving an average thickness of 3.5 to 4.5 mm.